Light emitting device

Abstract

A light emitting device is provided. The light emitting device includes a reflective layer, a conductive dielectric layer on the reflective layer and a semiconductor layer including an active layer on the conductive dielectric layer. And a distance “d” between the reflective layer and a light emitting portion of the active layer corresponds to a constructive interference condition. And the conductive dielectric layer includes a lower conductive dielectric layer on the reflective layer; an intermediate layer on the lower conductive dielectric layer and an upper conductive dielectric layer on the intermediate layer.

1 . A light emitting device comprising:
 a reflective layer;   a conductive dielectric layer on the reflective layer; and   a semiconductor layer comprising an active layer on the conductive dielectric layer,   wherein a distance “d” between the reflective layer and a light emitting portion of the active layer corresponds to a constructive interference condition, and   wherein the conductive dielectric layer comprises:   a lower conductive dielectric layer on the reflective layer;   an intermediate layer on the lower conductive dielectric layer; and   an upper conductive dielectric layer on the intermediate layer.   
     
     
         2 . The light emitting device according to  claim 1 , wherein the intermediate layer comprises a dielectric pattern. 
     
     
         3 . The light emitting device according to  claim 1 , wherein the conductive dielectric layer comprises a transparent conductive dielectric layer. 
     
     
         4 . The light emitting device according to  claim 1 , wherein the conductive dielectric layer comprises a conductive oxide layer. 
     
     
         5 . The light emitting device according to  claim 1 , wherein the conductive dielectric layer comprises a transparent conductive oxide layer. 
     
     
         6 . The light emitting device according to  claim 1 , wherein the intermediate layer comprises an intermediate dielectric layer. 
     
     
         7 . The light emitting device according to  claim 1 , wherein an average refractive index of the conductive dielectric layer is less than a refractive index of the semiconductor layer. 
     
     
         8 . The light emitting device according to  claim 1 , wherein a thickness of the light emitting layer is less than (½)×(λ/n). 
     
     
         9 . The light emitting device according to  claim 1 , further comprising a second conductive type semiconductor layer between the conductive dielectric layer and the active layer,
 and a distance “d” between the reflective layer and a light emitting portion of the active layer is set to the following equation:   d=(2m+1)/4×(λ/n)±α, where m is an integer equal to or greater than 0, λ is a wavelength of light emitted by the active layer, n is an average refractive index of a medium including the second conductive type semiconductor layer and the conductive dielectric layer between the active layer and the reflective layer, and α is a fluctuation range according to types of the reflective layer where α (⅛)×(λ/n).   
     
     
         10 . The light emitting device according to  claim 1 , wherein the reflective layer comprises at least one of Ag, Pt, and Al. 
     
     
         11 . The light emitting device according to  claim 11 , further comprising a first conductive type semiconductor layer on the active layer; and
 a photonic crystal structure on the first conductive type semiconductor layer,   wherein the dielectric pattern is identical or similar to a pattern of the photonic crystal structure.   
     
     
         12 . The light emitting device according to  claim 11 , wherein a depth of a hole or a height of a pillar structure in the photonic crystal structure is within 300 nm to 3,000 nm, and an average period of the photonic crystal is within 0.7 μm to 5 μm. 
     
     
         13 . The light emitting device according to  claim 2 , wherein the intermediate layer comprises a plurality of dielectric patterns, and a space between the dielectric patterns is filled with a second transparent conductive oxide 
     
     
         14 . The light emitting device according to  claim 2 , wherein the intermediate layer comprises a plurality of dielectric patterns, and a space between the dielectric patterns remains empty.